Herbert a



(No Model.)

H. A. BULLARD. commoner: FOR ELECTRIC SWITCHES.

Patented July 20,1897.

1 1 ATTORNEY THE mums ncrzns c0. PNoTO-LITHO.WASNINGTO n. c

UNiTnn STATES PATENT OFFICE.

HERBERT A. BULLARD, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR T THE STANLEY ELECTRIC MANUFACTURING COMPANY, OF SAME PLACE.

CONNECTION FOR E SPECIFICATION forming part of Letters Application filed May 5, 1897.

To all whom it may concern:

Be it known that I, HERBERT A. BULLARD, a citizen of the United States, residing at Pittsfield, in the county of Berkshire and State of Massachusetts, have invented certain new and useful Improvements in Electric Switches, of which the following is a full, clear, and exact description.

My invention relates to improvements in electric switches, and has for its object the provision of suitable means whereby the end of a wire may be electrically connected to one or both the switch-terminals, so as to be readily detachable therefrom, at the same time insuring a perfect contact, the said means being of a simple and inexpensivenature.

My invention is illustrated by the accompanying drawings, in which Figure l is a plan view of the lower end of the switchboard containing the finger-block of a lever-switch. Fig. 2 is a section on the line a: :0, Fig. 1; and Fig. 3 is a similar View, the electrical contact being broken. Fig. 4; illustrates a modification.

A is a switchboard. B is a block secured thereto in any desired well-known manner. C C are fingers projecting from said block and through which an electric circuit may be completed by means of a switch-lever of on dinary form. (Not shown.)

D is a nut carried by the block B, preferably in a recess in the outer face thereof. E is an annular groove in the outer surface of said nut. F F are pins, one or more of which may be provided, carried by said block B, the sides of said pins projecting slightly into the groove E in the block B, as shown clearly in Fig. 3. By this means it is manifest that while the nut maybe freely revolved it cannot become detached from the block without first removing the pins F F.

G is an opening in the switchboard A to the rear of the block B.

H is a tapered opening or seat in the rear of the block in line with the screw-threaded opening in the nut D.

I is a plug. J is a wire secured in the rear end of the plug. The free end of the plug I is screw-threaded to correspond with the in- LECTRIC SWITCHES.

Patent No. 586,543, dated July 20, 1897'. Serial No. 635,146. (No model.)

ternal screw-thread of the nut D. The end of the plug I adjacent said screw-threaded extremity is tapered to correspond substantially to the tapered opening in the rear of the block B.

In making connection it is merely necessary to insert the plug I through the opening G in the switchboard and into the opening II in the rear of the block B. By turning the nut D the screwthrcads of the parts D I are engaged and the plug I is drawn firmly into contact in the tapered opening or seatin the rear of the block, thereby perfecting the electrical connection. To detach said plug, the nut D is turned in the reverse direction, and inasmuch as the nut I) cannot become accidentally detached from the block B the plug is moved in an opposite direction (110 matter how tight the connection in the tapered opening is) and so that the parts may be readily separated. This means is of particular value in connection with electrical equip ment, where the perfection of the contact is an important element, and in connection with electric switches of varying types it possesses great merit, as the connection may be readily broken without marring or injuring in any way the terminal block or the switch board, as is frequently done in the ordinary construction where the parts have become set or corroded, thus requiring great power to effect the separation.

The nut may be provided with a slot to receive the screw-driver, or, if preferable, may have flattened sides to receive the Wrench. This means of connection may be provided for the block which carries the switch-lever (not shown) or for any other part where it is desired to provide a simple and effective de tachable connection.

An example of a modification is shown in Fig. 4., in which the tightening and loosening means, the nut D, is carried by the plug 1 instead of by the block B, and the annular groove is formed in the plug instead of in the nut, as in the previous case, and the retaining-pins F F are carried by the nut instead of the block and the screw-threads on the nut cooperate with screw-threads on the block B instead of on the plug.

What I claim is 1. Inan electric connection, a supporting means, a' tapered opening therein, a detachable tapered plug, a nut loosely carried by one of said parts, holding means therefor, to permit the nut to be freely revolved, said means preventing independent longitudinal movement of said nut with respect to its supporting means, a screw-thread connection by which said parts are attached or detached.

2. In an electrical connection, a block having a tapered opening, a nut, carried by said block and capable of being revolved independently thereof, holding means to prevent said nut from moving in a longitudinal direction, independently of said block, a plug having a screw-threaded extremity, thesides of said plug adjacent said screw-threaded extremity being tapered to correspond substantially to the tapered opening in the block.

3. In an electrical connection, a block having a tapered opening in one side, a recess in the opposite side, a nut carried in said recess, an'annular groove around said nut, pins carried by said block and projecting into said annular groove in said nut, a tapered plug screw-threaded at its extremity to correspond with the'screw-thread of said nut.

4. In an electrical connection, a block, a tapered opening in one side thereof, a recess in the opposite side thereof, a nut carried in said recess and means to prevent disengagement of said nut from said block, a tapered plug, said plug being screw-threaded at its extremity to correspond with the screw-thread of said nut.

5. In an electric switch, a board, a metallic block secured thereto, a tapered opening in the rear of said block adjacent to said board, an opening in' said board concentric.

HERBERT A. BULIIARD.

Witnesses:

F. M. PLATT, JOHN F. KELLY. 

